Issue #21703: Add test for undo delegator. Patch most by Saimadhav Heblikar .

Lib/idlelib/UndoDelegator.py

@@ -336,30 +336,33 @@ class CommandSequence(Command):
         self.depth = self.depth + incr
         return self.depth
 
-def _undo_delegator(parent):
-    from idlelib.Percolator import Percolator
-    root = Tk()
-    root.title("Test UndoDelegator")
-    width, height, x, y = list(map(int, re.split('[x+]', parent.geometry())))
-    root.geometry("+%d+%d"%(x, y + 150))
 
-    text = Text(root)
-    text.config(height=10)
+def _undo_delegator(parent):  # htest #
+    import re
+    import tkinter as tk
+    from idlelib.Percolator import Percolator
+    undowin = tk.Toplevel()
+    undowin.title("Test UndoDelegator")
+    width, height, x, y = list(map(int, re.split('[x+]', parent.geometry())))
+    undowin.geometry("+%d+%d"%(x, y + 150))
+
+    text = Text(undowin, height=10)
     text.pack()
     text.focus_set()
     p = Percolator(text)
     d = UndoDelegator()
     p.insertfilter(d)
 
-    undo = Button(root, text="Undo", command=lambda:d.undo_event(None))
+    undo = Button(undowin, text="Undo", command=lambda:d.undo_event(None))
     undo.pack(side='left')
-    redo = Button(root, text="Redo", command=lambda:d.redo_event(None))
+    redo = Button(undowin, text="Redo", command=lambda:d.redo_event(None))
     redo.pack(side='left')
-    dump = Button(root, text="Dump", command=lambda:d.dump_event(None))
+    dump = Button(undowin, text="Dump", command=lambda:d.dump_event(None))
     dump.pack(side='left')
 
-    root.mainloop()
-
 if __name__ == "__main__":
+    import unittest
+    unittest.main('idlelib.idle_test.test_undodelegator', verbosity=2,
+                  exit=False)
     from idlelib.idle_test.htest import run
     run(_undo_delegator)

Lib/idlelib/idle_test/test_undodelegator.py

@@ -0,0 +1,134 @@
+"""Unittest for UndoDelegator in idlelib.UndoDelegator.
+
+Coverage about 80% (retest).
+"""
+from test.support import requires
+requires('gui')
+
+import unittest
+from unittest.mock import Mock
+from tkinter import Text, Tk
+from idlelib.UndoDelegator import UndoDelegator
+from idlelib.Percolator import Percolator
+
+
+class UndoDelegatorTest(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        cls.root = Tk()
+        cls.text = Text(cls.root)
+        cls.percolator = Percolator(cls.text)
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.percolator.redir.close()
+        cls.root.destroy()
+        del cls.percolator, cls.text, cls.root
+
+    def setUp(self):
+        self.delegator = UndoDelegator()
+        self.percolator.insertfilter(self.delegator)
+        self.delegator.bell = Mock(wraps=self.delegator.bell)
+
+    def tearDown(self):
+        self.percolator.removefilter(self.delegator)
+        self.text.delete('1.0', 'end')
+        self.delegator.resetcache()
+
+    def test_undo_event(self):
+        text = self.text
+
+        text.insert('insert', 'foobar')
+        text.insert('insert', 'h')
+        text.event_generate('<<undo>>')
+        self.assertEqual(text.get('1.0', 'end'), '\n')
+
+        text.insert('insert', 'foo')
+        text.insert('insert', 'bar')
+        text.delete('1.2', '1.4')
+        text.insert('insert', 'hello')
+        text.event_generate('<<undo>>')
+        self.assertEqual(text.get('1.0', '1.4'), 'foar')
+        text.event_generate('<<undo>>')
+        self.assertEqual(text.get('1.0', '1.6'), 'foobar')
+        text.event_generate('<<undo>>')
+        self.assertEqual(text.get('1.0', '1.3'), 'foo')
+        text.event_generate('<<undo>>')
+        self.delegator.undo_event('event')
+        self.assertTrue(self.delegator.bell.called)
+
+    def test_redo_event(self):
+        text = self.text
+
+        text.insert('insert', 'foo')
+        text.insert('insert', 'bar')
+        text.delete('1.0', '1.3')
+        text.event_generate('<<undo>>')
+        text.event_generate('<<redo>>')
+        self.assertEqual(text.get('1.0', '1.3'), 'bar')
+        text.event_generate('<<redo>>')
+        self.assertTrue(self.delegator.bell.called)
+
+    def test_dump_event(self):
+        """
+        Dump_event cannot be tested directly without changing
+        environment variables. So, test statements in dump_event
+        indirectly
+        """
+        text = self.text
+        d = self.delegator
+
+        text.insert('insert', 'foo')
+        text.insert('insert', 'bar')
+        text.delete('1.2', '1.4')
+        self.assertTupleEqual((d.pointer, d.can_merge), (3, True))
+        text.event_generate('<<undo>>')
+        self.assertTupleEqual((d.pointer, d.can_merge), (2, False))
+
+    def test_get_set_saved(self):
+        # test the getter method get_saved
+        # test the setter method set_saved
+        # indirectly test check_saved
+        d = self.delegator
+
+        self.assertTrue(d.get_saved())
+        self.text.insert('insert', 'a')
+        self.assertFalse(d.get_saved())
+        d.saved_change_hook = Mock()
+
+        d.set_saved(True)
+        self.assertEqual(d.pointer, d.saved)
+        self.assertTrue(d.saved_change_hook.called)
+
+        d.set_saved(False)
+        self.assertEqual(d.saved, -1)
+        self.assertTrue(d.saved_change_hook.called)
+
+    def test_undo_start_stop(self):
+        # test the undo_block_start and undo_block_stop methods
+        text = self.text
+
+        text.insert('insert', 'foo')
+        self.delegator.undo_block_start()
+        text.insert('insert', 'bar')
+        text.insert('insert', 'bar')
+        self.delegator.undo_block_stop()
+        self.assertEqual(text.get('1.0', '1.3'), 'foo')
+
+        # test another code path
+        self.delegator.undo_block_start()
+        text.insert('insert', 'bar')
+        self.delegator.undo_block_stop()
+        self.assertEqual(text.get('1.0', '1.3'), 'foo')
+
+    def test_addcmd(self):
+        text = self.text
+        # when number of undo operations exceeds max_undo
+        self.delegator.max_undo = max_undo = 10
+        for i in range(max_undo + 10):
+            text.insert('insert', 'foo')
+            self.assertLessEqual(len(self.delegator.undolist), max_undo)
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2, exit=False)